This invention relates in general to bearings and more particularly, to a sleeve or liner-type plain rotary bearing. Most particularly, the invention relates to a multi-layer bushing.
A bushing is generally a fixed or removable cylindrical lining used to constrain or guide a shaft or reduce friction between moving parts. Bushings are generally formed of plastic or soft metal, such as nylon or brass, or graphite-filled sintered metal.
The low friction property of a bushing renders the bushing prone to slip or rotate. Moreover, the soft, pliable property limits a bushing""s ability to be fit tightly within its working environment. Bushings made of graphite-filled sintered metal may have greater application in environments where a tight fit is desirable but such bushings are costly in comparison to plastic or soft metal bushings.
Plastic bushings may be a relatively low-cost alternative. However, plastic has a tendency to sink, shrink or otherwise change shape, especially when forming a relatively thick bushing. The resultant bushing is distorted to the extent that its inner and outer diameters are inconsistent. Even if a relatively thick plastic bushing were formed without distortion, the resultant bushing would encounter deformation when subjected to a load.
What is needed is a low-cost bushing which may be formed without distortion and which does not encounter deformation when subjected to a load.
The present invention is directed towards a low-cost bushing that is formed without distortion and which does not deform when subjected to a normal load. The bushing comprises a main body that is adapted to be supported by the first member. The main body is comprised of a rigid layer and one or more other layers supported by the rigid layer. One of the layers defines an axial bore that is adapted to receive a pin that movably couples the second member to the first member.
Various objects and advantages of this invention will become apparent to those skilled in the art from the following detailed description of the preferred embodiment, when read in light of the accompanying drawings.